Growing Food: A Guide to Food Production

Diseases: also not normally a big problem, though Alternaria Leaf Spot may cause
the leaves to fall off in humid conditions. Other diseases include Bacterial Leaf Spot,
Cotton Root Rot (in cold, wet soils), Rust and Grey Mould (in warm, humid
conditions). Modern varieties have partial resistance to some diseases.

YIELD
The average for annual varieties of castor in dryland conditions varies from about
500 kg/ha in India and Africa to 1700 kg/ha in France. Irrigated castor should yield
2.5–3 MT/ha; some hybrid dwarf varieties can produce 5 MT/ha and more.
The FAO estimate for the global average seed yield in 2004 was 1.07 MT/ha,

Perennial castor varieties are not normally grown in pure stands but are widely
spaced all over the farm, either alone or as part of a mixed cropping system.

UTILISATION

• Traditionally this has been used as a medicine, for lighting and for the curing of


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  fanlike leaves.

  
  

LIMITATIONS

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  stems and can be dangerous to animals (and humans) which eat them. These
  substances must also be removed from the oilcake before it is safe to be eaten

  
  


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  if it is harvested manually. With mechanical harvesting, some of the seed is too
  green and some will have shattered from mature pods, creating unwanted

  
  


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  castor.

  
  

from a maximum of 1.24 MT/ha in India to a minimum of 231 kg/ha in Kenya.

192 TONY WINCH

hides and skins.

an insecticide is extracted from the leaves.

Ethiopia and places where Ethiopians eat together.

The castor pomace presscake is used mainly as a fertiliser, or as animal food.

The plants can be used as a shade crop, to protect coffee bushes for example.

The seed or “bean” contains 35–60% of a highly valued non-drying oil.

The seed can be crushed and used to spread on enjera plates before cooking, in

They are also used in landscaping for their attractive giant, twelve-lobed,

volunteers the next season.

The plant requires hot conditions and it is sensitive to frost.

by animals.

nutrients.

The castor plant is a heavy feeder which depletes the soil of large amounts of

Ricin and an allergen are toxic substances present in the seed, leaves and

The seed clusters mature unevenly, so that two or more harvests must be made

Low yields combined with low prices often discourage farmers to cultivate